Said is a 32-year-old male who has recently emigrated to the UK from Nepal. He attends his GP practice with regards to symptoms of weight gain, tiredness and hoarseness of voice. Following blood tests, including a thyroid function test, it is found that he has hypothyroidism. What is the most likely cause of hypothyroidism in this patient? A-Hashimoto's thyroiditis B-Iodine deficiency CThyroid adenoma D-Toxic multinodular goitre E-De Quervain's thyroiditis